The invention relates generally to the use of device color profiles used by image color management systems.
One goal of image color management technology is to ensure that a color image, graphic, or text object (hereinafter collectively referred to as graphical objects) is rendered as close as possible to its original intent on any device, despite differences in imaging technologies and color capabilities between devices. To achieve this goal, color characteristics of devices such as scanners, printers, and display monitors may be determined a priori and encapsulated in a device profile.
A device profile is a file that contains information about how to convert colors in the color space of a specific input device (e.g., a scanner) into a device-independent color space, or from a device independent color space into an output device's color space. Typical input and output device color spaces include the red-green-blue (RGB) and cyan-magenta-yellow-black (CMYK) color spaces. One illustrative device-independent or profile color space (PCS) is the Commission Internationale de lÉclairage (CIE) XYZ color space. (See Commission Internationale de lÉclairage Publication 15.2-1986, “Colorimetry, Second Edition.”)
Referring to FIG. 1, computer system 100 may include one or more graphical applications 102 that can be used to view and/or modify graphical objects generated by a device such as a digital scanner. Applications 102 may communicate with color management module (CMM) 110, through application programming interface (API) 104 and graphics 106 and imaging 108 libraries. Profiles 112 may provide CMM 110 with information about how to convert colors into and out of device color spaces. For example, if the input device is a color scanner, a first profile may provide CMM 110 with information needed to convert the scanner's input color space (e.g., the red-green-blue, RGB) into the PCS. A second profile may provide the necessary information for CMM 110 to convert the PCS into a suitable output color space such as for viewing on a display monitor. One example output color space is the sRGB color space as described in version 1.10 of the document entitled “A Standard Default Color Space for the Internet—sRGB,” published by members of Hewlett-Packard Company and Microsoft Incorporated in 1996.
Input and output device profiles 112 are typically created by device manufacturers or third party vendors and may comprise one, or a few different profiles—where each profile may accommodate different input and output color spaces. In an environment in which one, or at most a few, profiles for each device can be determined a priori, the above described color management scheme may work reasonably well. In an environment in which graphical objects may be subject to a variety of different capture environments (such as images generated by a digital camera), however, a single a priori device profile cannot provide good color reproduction for the different capture environments. Thus, it would be beneficial to provide a technique (apparatus and method) to generate color profiles for graphical objects in a dynamic or automatic fashion.